What is the chronological order of the Halo novels?

This is a question not easily answered. Although most Halo novels span time with no overlap, some of the Halo novels digress into history, or cover events that take place during the same time as the other novels.

Halo books in order

The quick answer? Using the bulk of each novel, many sources tend to agree to this order:

Halo: Forerunner Trilogy
Halo: Contact Harvest
Halo: The Cole Protocol
Halo: The Fall of Reach
Halo: The Flood
Halo: First Strike
Halo: Ghosts of Onyx
Halo: Evolutions (spans from about a year before covenant war to six years after)

The long answer on the chronological order of the Halo novels?

Opinions differ across the net, and one of the most detailed timelines for the Halo novels can be found at wikipedia. Here is a list compiled from that source, including the Halo games into the timeline for comparison: